Oxalic acid diarylamides

ABSTRACT

Disclosed are oxalic acid diarylamides as ultraviolet absorbing agents for organic materials, the oxalic acid diarylamides being compounds of the formula

ite States Biland et al.

[4 1 Sept. 16, 1975 OXALIC ACID DIARYLAMIDES [75] Inventors: Hans RudolfBiland, Basel; Max

Duennenberger, Frenkendorf; Christian Luethi, Muenchenstein, all ofSwitzerland Related U.S. Application Data [60] Continuation-in-part ofSer. No. 879,964, Dec. 4, 1969, abandoned, which is a division of Ser.Nov 599,363, Dec. 6, 1966, Pat. No. 3,542,573.

[52] U.S. Cl. 260/479 R; 260/476 R; 260/473 F; 260/459 NC; 260/465 D;260/513 R;

260/518 R; 260/556 B; 260/558 A; 260/559 [51] Int. Cl. C07C 103/30 [58]Field of Search 260/559, 479, 473, 476

[56] References Cited FOREIGN PATENTS OR APPLICATIONS 1.332.227 6/1963France 260/559 Primary E.\'uminerHarry l. Moatz [57] ABSTRACT Disclosedare oxalic acid diarylamides as ultraviolet absorbing agents for organicmaterials, the oxalic acid diarylamides being compounds of the formulaANHCO-CONH-A in which A represents a member selected from the groupconsisting of in which Z represents a member selected from the groupconsisting of a linear or branched alkyl group with 1 to 18 carbonatoms, an acetyl, butyryl, lauroyl, octadecanoyl, benzoyl, para-tertiarybutylbenzoyl or para-chlorobenzoyl group, a benzyl group, acarbalkoxyalkyl group with a total of up to 12 carbon atoms, an allylgroup and a mono-halogenalkyl group with up to 8 carbon atoms; Zrepresents an alkyl or monohalogenalkyl group containing 1 to 18 carbonatoms; R represents an alkyl group containing 1 to 12 carbon atoms, w is1, 2 or 3; X represents a member selected from the group consisting ofan alkyl group with up to 12 carbon atoms, a halogen atom, a phenyl anda cyclohexyl group; and Y and Y each stands for hydrogen, an alkyl oralkoxy group with 1 to 8 carbon atoms, or Y may also represent a phenylgroup; W represents an alkyl group with l to 18 carbon atoms or acarbalkoxyalkyl group with 3 to 8 carbon atoms.

9 Claims, No Drawings This is a continuation-in-part of our copendingapplication Ser. No. 879,964 filed Dec. 4th, 1969, now abandoned whichin turn, is a divisional application of Ser. No. 599,363, filed Dec. 6,1966, now U.'S. Pat. No. 3,542,573.

The present invention provides symmetrical oxalic acid diarylamides thathave proved particularly suitable for the protection of organicmaterials, which may be damaged by the action of light, especiallyultraviolet rays, in a variety of ways, from the action of suchirradiation.

While it is already known that certain oxalic acid bis hydroxyarylamidesare suitable as light filters against ultraviolet irradiation, it hadbeen thought in the past that the light stability of such compounds isconditional upon the presence of a free hydroxyl group in orthopositionto the amide nitrogen. Contrary to this assumption it has now been foundthata large group of oxalic acid diarylamicles that do not conform withthe said prerequisite are not only ultraviolet absorbers producingexcellent results in industrial applications but,

surprisingly, even display a higher light stability. The symmetricaloxalic acid diarylamides ofthe formula 4 5 R5 R (1) I are homogeneouslydistributed in the organic materials, to be protected, or applied to thesurface of said materials, or the materials to be protected are placedunderneath a filter layer incorporating the compounds defined, In theformula (1) the symbols R to R each represents a hydrogen atom, ahalogen atom, a substituent containing up to 20 carbon atoms from theseries alkyl, substituted alkyl, benzene radical, benzyl group, anitrile group, a possibly substituted alkoxy group, alkenyloxy group, analiphatic or aromatic acyl group, one of the groups OCOHNX, CONH-X or SONHX (where X stands for hydrogen, alkyl or aryl), a group COOY or -SO Y(where Y stands for hydrogen, alkyl, aryl or a salt-formingcation), anitro group, an amino group or an acylamino group. The substituents Rand R or R and R together with the benzene ring to which they areattached may also form a fused on six-membered carbocycle, and where a.each benzene nucleus contains at most two substituents -OCONH-X, CONHX,SO- NH-X, COOY, -S -,X, alkoxy or alkenyloxy, b. each benzene nucleuscontains at most three of the other substituents different fromhydrogen, and c. at least one of the substituents R to R is differentfrom hydrogen. I Within the scope of this definition halogen is, forexample, above all chlorine or bromine; alkyl is a branched'or linearalkyl radical having a small number of carbon atoms (C to C,,) or higheralkyls containing 5 to 18 carbon atoms (for example octyl, 'dodecyl andthe like), a substituted alkyl radical'being'chloralk yl, bromalkyl,hydroxyalkyl, alkcnyloxyalkylg:*carboxyalkyl or carbalkoxyalkyl; asubstituted alkoxy group is a halogenalkoxy, cyanalkoxy, hydroxyalkoxy,carbalkoxyalkoxy, SO X or a phenylalkoxy group; alkenyloxy is above allallyloxy;,an acyl group is, for example, acetyl, butyryl, lauroyl,octadecanoyl, benzoyl, paratertiary butylbenzoyl or para-chlorobenzoyl;acylamino groups are acetylamino and benzoylamino; amino groups may alsobe substituted, being methylamino or ethylamino, as well as the anilinogroups. Within the scope of the formula l there are also the symmetricalcompounds of the formula in which R,, to R are identical or differentand each represents a hydrogen atom, a halogen atom, an alkyl or alkoxygroup containing 1 to 18 carbon atoms, or a phenyl group, and in whicha. each benzene nucleus contains at most two alkoxy groups, b. eachbenzene nucleus contains at most three substituents different fromhydrogen, and c. at least one of the substituents R to R is differentfrom hydrogen. Within the scope of the formula (1) there are alsocompounds of the formula in which R,; to R are identical or differentand each represents a hydrogen atom, an aliphatic or aromatic acyl groupcontaining 1 to 12 carbon atoms, one of the groups OCOHNX, CONHX or SO-NHX (where X stands for hydrogen, an alkyl group with l to 4 carbonatoms or phenyl), a group COOY or -SO Y (where Y is hydrogen, alkyl withl to 4 carbon atoms, phenyl, or. an alkali metal, ammonium or amine saltion) and where each benzene nucleus contains one or two of theabove-mentioned sub stituents different from hydrogen and at least oneof the substituents R',, to R,,, is different from hydrogen.

In the case of the aniline or substituted aniline derivatives compoundsof the formula are of practical interest. In this formula R and R areidentical or different and each represents chlorine, bromine,,alkyl withl to 4 carbon atoms, alkoxywith l to 18 carbon atoms or a nitro group,or one of the substituents R or R represents a hydrogen atom, acarboxylic acid group, a carboxylic acid alkyl ester group containing lto 8 carbon atoms in its alkyl grouping, a sulphonic acid group or asulphonamide group, or R represents an etherified or acylated hydroxylgroup which is etherified (especially alkyl ethers) or acylated with asuitable group containing 1 to 18 carbon atoms. Some variants of suchtypes of compounds correspond to the following formulae in which Rrepresents a hydrogen atom, or an alkoxy group with 1 to 18 carbonatoms, with the proviso that at least one R per phenyl group representssuch an alkoxy group,

R represents a hydrogen atom, a chlorine or bromine atom, with theproviso that at least one R per phenyl group represents one of thesehalogen atoms, and

R represents a hydrogen atom or an alkyl group with l to 4 carbon atoms,with the proviso that at least one R per phenyl group represents such analkyl group,

Another type of compound suitable for protecting a-olefine polymers andpolyvinylchloride corresponds to the general formula R O NH GO CO 111iO-R where R is an alkyl group with up to 18 carbon atoms, a benzylgroup, an acyl group or an ally] group. In this group there are alsocompounds of the formula o .4111 co 00 1mwhere R represents a methyl,ethyl, octyl or octadecyl radical, The present invention providessymmetrical oxalic acid diarylamides of the formula ANHCO-CONH-A inwhich A represents a member selected from the group consisting of CH w 2in which Z represents a member selected from the group consisting of alinear or branched alkyl group with 1 to 18 carbon atoms, an acetyl,butyryl, lauroyl, octadecanoyl, benzoyl, para-tertiary butyl-benzoyl orpara-chlorobenzoyl group, a benzyl group, a carbalkoxyalkyl group with atotal of up to 12 carbon atoms, an allyl group and a mono-halogenalkylgroup with up to 8 carbon atoms; Z represents an alkyl ormonohalogenalkyl group containing 1 to 18 carbon atoms; R represents analkyl group containing 1 to 12 carbon atoms, w is l, 2 or 3; Xrepresents a member selected from the group consisting of an alkyl groupwith up to 12 carbon atoms, a halogen atom, a phenyl and a cyclohexylgroup; and Y to Y each stands for hydrogen, an alkyl or alkoxy groupwith l to 8 carbon atoms, or Y may also represent a phenyl group; Wrepresents an alkyl group with l to 18 carbon atoms. or acarbalkoxyalkyl group with l to 8 carbon atoms, preferably 3 to 8 carbonatoms.

Ofspecial value within the scope of the formula 10) are those compoundswhich correspond to the formula and more especially those oxalic aciddiarlyamides In the above formulae (1 l) and (12) Z, X and Y to Y havethe same meanings as in formula (10). In formula l 1 preferably only oneor two of the symbols Y, to Y and X represent substituents differentfrom hydrogen atoms, as indicated above.

A subgroup of compounds of the above formula l 1 which are particularlyvaluable for practical use in cludes also those compounds of the formulal l as defined, in which, however, at least one of the substituents Y orX or both these substituents represent a tertiary butyl group.

Specific groups of compounds according to the above general formulaecorrespond to the following formulae (where Z has the meaning definedabove):

Of special importance are also oxalic acid diarylamides of the formula-1TH CO-CO-- NH" in which w l. 2 or 3 and R represents an alkyl radicalwith l to 12 carbon atoms; also oxalic acid diarylamides of the formulain which Z represents an alkyl group with l to 18 carbon atoms or ahalogenalkyl group, preferably monohalogenalkyl.

From the group of the naphthylamine derivatives according to the generalformula (1 there may be mentioned, for example, those of the formula Inthis formula the brackets indicate that both a-naphthylamine and,B-naphthylamine derivatives are possible; R represents a hydrogen atom,a lower alkyl group with 1 to 4 carbon atoms, a sulphonic acid group oran etherified hydroxyl group; m l or 2 in the case of the sulphonic acidgroup, but otherwise it is I.

From among the novel naphthylamine derivatives there may be mentionedabove all those which have already been described in connection withformula :hat is to say primarily compounds of the formula n which Wrepresents an alkyl group with l to 18 car- )Ol'l atoms or ancarbalkoxyalkyl group with l to 8 car on atoms, preferably 3 to 8 carbonatoms.

From the large variety of oxalic acid diarylamides hat can be used inthis invention there may be menioned the following non-limitingexamples: Oxalic acid iarylamides derived from the under-mentioned anines: Aniline, 2-chloraniline, 4chloraniline, 3- hloraniline,2,4-dichloraniline, 3,4-dichloraniline,

,4,6-trichloraniline and the corresponding bromani-- naphthylamine andof the following sulphonic acids the naphthylamines:l-naphthylamine-4-sulphonic id, 1 l-naphthylamine-5 sulphonic acid,iaphthylamine-8-sulphonic acid. 2-naphthylamine-5- phonic acid,2-naphthylamin'c-4,8-(lisulphonic acid,

8 2-naphthylamine6,8-disulphonic acid, 8hydroxyl naphthylamine4-sulphonic acid, 8hydroXy-2 naphthylamine6-sulphonic acid, 8-hydroxylnaphthylamine-4,6-disulphonic acid, 8-hydroxyl.-

naphthylamine-3,6-disulphonic acid and 8-hydroxy-2-naphthylamine-3,o-disulphonic acid.

The oxalic acid bis-arylamides of the general formula (1) are accesibleby known methods, for example, by reacting oxalic acid compounds of thegeneral formula in which Q represents a halogen atom, such as chlorine,

or the hydroxyl group or the OT group, T representing an aliphatic oraromatic hydrocarbon radical, preferably the methyl or ethyl group, witharylamines of the benzene or naphthalene series corresponding to theformula (II) R HZN R3 1 in which R to R have the meanings given informula (I) substantially in the molecular ratio of 1:2, at temperaturesbetween 0 and 220C in solution or in a melt, in the presence of an inertsolvent, such as benzene, dichlorobenzene, tetrachlorethane ordiethylcarbitol, if desired or required in the presence of a catalyst,such as boric acid, the reaction being conducted in such manner thathydrohalic acid, water, or alcohols or phenols are split off, and liquidbyproducts are eliminated from the reaction mixture, preferably by azeotropic distillation.

Compounds in which the radicals R to R are ether or ester groups canalso be obtained from intermediate products containing phenolic hydroxylgroups by subsequent etherification or esterification in per seconventional manner. The novel symmetrical oxalic acid diarylamides ofthe formula ANHCOCON- H.A (I0) i where A has the same meaning aspreviously described are also synthesized by the above described processby reacting primary amines or the formula;

sulphanilamide,

HO a: H0 H0 H N 1 H 1 2 2 a N 2 2 O x I it where Y Y Y X. has the samemeaning as previously defined with oxalic acid compounds of formula (I).Then the groups Z, W, 2,, R where Z, W, Z, R have the same meaning as informula (10), are introduced by esterification or etherification of thefree phenolic group of the resulting product. Alternatively the groupsZ, W, Z R can be initially introduced by etherification of the phenolicgroup of the primary amines of formula 10 a, 10 b, 10 c, 10 d, and thensubsequent condensation of the resulting ether with oxalic acid compoundof formula (I) to give the final product. The procedure of esterficationor etherifi- OH H C cation of phenolic group which leads to esters,ethers,

alkylethers, alkenylethers is fully described in Fr 2 A few examples ofthe reagents which can be used to esterify or etherify the phenolicgroup of the above described compounds are, benzoyl chloride, p-

NH m 2 H -H -H c 2 1 H000 H20 I 000 2 2 El HC2OOC [1 0 H O 2 OH CLI OH 2NH 2 2 61 OH chlorobenzoyl chloride, chloroethyl acetate, 3- chloroethylpropionate, 4-chloroethyl butyrate, etc. These reagents as well asothers are available from Aldrich chemical company, Fluka A.G. ChemiseFabrik and other well known chemical companies,

Some of the starting materials are commercially available while otherscould be obtained from available compounds by known methods. Theconventional methods consist of introducing nitrogen functions such asNO NO, -N=NAr, in ortho-position to the phenolic group of availablephenol or naphthol and then subsequent reduction of the nitrogenfunction to amino group. A good yield of the desired aminophenol oraminonaphthol is usually obtained, since the nitrogen function isintroduced exclusively in the orthoposition to the phenolic group whenthe para-position is blocked by substituents as in formulae 10 a, and 10b. Illustrative examples of these conventional methods are given below.

a. Viu-Nitration and subsequent reduction 2 H (at U on OH The method ofpreparation of the above phenols is fully described in J. Am. chem.Soc., 71,1265 (1949), 76,4985-4988 (1954).

b. Viu Nitroso-derivative and subsequent reduction 10 The method ofpreparation of this naphthol is described in Org. Syntheses, Coll. Vol.,II 33 (1943) c. Via Azo-derivative and subsequent reduction The methodof preparation of the above compounds is 0 fully described in Ann.,369,209 (1909), Ber., 39,2494

(1906 J. Amer. chem. Soc., 71,1265 (1969), 76,4985 1954).

By employing the above methods the starting materials listed below aresynthesized.

Some of the aminophenolic ethers employed as starting 35 materials arecommercially available as for example 2- methoxyaniline,2-ethoxyaniline, while others are syntherized by known methods. The mostcommon method consist of etherification of the available phenol,nitration of the resulting phenolicether and subsequent reduction of thenitro group to amino group. I1-

lustrative examples are the following:

NH NH H Co 2 cuii 2 Ngca H.5CO oca H 2 11 Cl 00 11 3:11 N

2 H5C (I: CH.

5 OC H n NH NH H o- H an 5 OH OH H c g 2 Isooc'tyl 2 5 ca OH OH IsooctylW Q Isooc cyl- OH H OH tert. amyl 2 tert.amyl

The preparation of the above compounds is more fully described in J.Amer. Chem. Soc., 76,4985 (1954), U.S. Pat. No. 2,581,972 and Britishintelligence official subcommitte, Final Report, 986, I 1946) Thepreparation of aminophenol corresponding to formula d) is described indetail in J. Chem. Soc, 980, (1954).

The compounds of the above formulae (1) and the following are inprinciple suitable for stabilizing and protecting all those organicmaterials which are in any form damaged or destroyed upon exposure toultraviolet rays. Such dosage due to the effect of the same agent,namely ultraviolet irradiation, may have widely disparate results, forexample discoloration, changes in the mechanical properties(brittleness, fissuring, tear strength, flexural strength, abrasionresistance, elasticity, aging), triggering of undesired chemicalreactions (decomposition of delicate chemical substances, for examplemedicaments), photochemically induced rearrangements, oxidation and thelike (for example of oils containing unsaturated fatty acids) thecausing of burns and irritation (for example on human skin) and thelike.

Accordingly, the organic materials to be protected may belong to a widevariety of types of substances and be present in widely differentprocessing stages and physical states, whereas they all have the commoncharacteristic of being sensitive towards ultraviolet irradiation.

Organic materials of this kind may be of a high molecular or lowmolecular nature.

As nonlimiting examples of low molecular and high molecular substancesthat can be protected or stabilized by compounds of the instantinvention, there may be mentioned:

Organic natural substances used for pharmaceutical purposes(medicaments), ultraviolet-sensitive dyestuffs, compounds which in theform of victuals or when present in victuals are decomposed byirradiation (unsaturated fatty acids in oils) and the like.

As examples or organic substances of high molecular weight there may bementioned:

I. Synthetic organic materials of high or higher molecular weight suchas:

a. Polymerization products based on organic compounds containing atleast one polymerizable carbon-to-carbon double bond, that is to saytheir homopolymers or copolymers as well as their aftertreatingproducts, for example crosslinking, grafting or decomposition products;diluted polymers; modification products obtained by modifying reactivegroupings in the polymer molecule and the like, for example polymersbased on 01,,B-unsaturated carboxylic acids (for example acrylates,acrylamides, acrylonitrile), of olefinic hydrocarbons, for examplea-olefines, ethylene, propylene or dienes, that is to say also rubbersand rubberlike pol ymers (also socalled ABS polymers), polymers based onvinyl and vinylidene compounds (for example styrene, vinyl esters,vinylchloride, vinyl alcohol), of halogenated hydrocarbons, ofunsaturated aldehydes and ketones, allyl compounds and the like;

b. other polymerization products obtainable, for example, by ringopening, for instance polyamides of based on bifunctional orpolyfunctional compounds containing condensable groups, theirhomocondensates and cocondensate as well as their after-treatmentproducts, such, for esample, as polyesters [saturated (e.g. polyehtyleneterephthalate) or unsaturated (e.g. maleic aciddialcohol polycondensatesand their crosslinked products with copolymerizable vinyl monomers),linear or branched (also those based on polyhydric alcohols, e.g. alkydresins)], polyamides (e.g. hexamethylenediamine adipate, maleinateresins, melamine resins, phenolic resins (e.g. novolaks), anilineresins, furan resins, carbamide resins and their precondensates andsimilarly constituted products; polycarbonates, silicone resins and thelike.

d. Polyadducts, such as polyurethanes (crosslinked and not crosslinked);epoxy resins.

ll. Semisynthetic organic materials, for example cellulose esters andmixed esters (cellulose acetate or propionate), nitrocellulose,cellulose ethers, regenerated cellulose (viscose rayon, cuprammoniumcellulose) or their after-treatment products; casein synthetics.

III. Natural organic materials of animal or vegetable origin, forexample those based on cellulose or proteins such as wool, cotton, silk,bast, jute, hemp, pelts and hairs, leathers, finely divided wood pulp,natural resins (such as colophony, especially lacquer resins), gelatin,

' glues, also rubber, gutta percha, balata and their aftertreatment andmodification products, degradation products, products accessible bymodification of reactive groups.

The organic materials concerned may be at widely differing stages oftheir processing (raw materials, semifinished products or finishedproducts) and physical states. They may be in the form of productsshaped in a wide variety of ways, that is to say, for example, aspredominantly three-dimensional objects such as sections, vessels orcomponents of a great variety, chips or granules, foamed products;predominantly twodimensional materials such as films, foils, lacquers,impregnations or coatings or predominantly unidimensional materials suchas filaments, fibres, flocks, bristles or wires. The said materials mayalso be in unshaped states in a wide variety of homogeneous orinhomogeneous forms of distribution and physical states, for example inthe form of powders, solutions, normal and reversed emulsions (creams),dispersions, latices, sols, gels, putties, waxes, adhesives or porefillers, and the like.

Fibrous materials may be used in a wide variety of processing forms, forexample as textile threads, yarns, fibre fleeces, padding, flocculatedmaterials or as textile fabrics or textile laminates, knitwear, papers,cardboards and the like.

The new stabilizers may also be used, for example, as follows:

a. In cosmetics, such as perfumes, dyed or undyed soaps and bath salts,skin and face creams, powders, repellants and especially sunburn oilsand creams;

b. in admixture with dyestuffs or pigments or as additives to dyebath,printing, discharge or reserve pastes, also for after-treating dyeings,prints or dis charge prints;

c. in admixture with so-called carriers, antioxidants, other lightfilters, heat stabilizers or chemical bleaches;

d. in admixture with crosslinking agents or dressing agents such asstarch or synthetically produced dressings;

e. in combination with detergents (the detergents and stabilizers may,if desired, be added separately to the washing liquors);

in gelatin layers used in photography;

g. in combination with polymeric vehicles (products of polymerization,polycondensation or polyaddition) in which the stabilizers, if desiredin addition to other substances, are incorporated in the dissolved ofdispersed form, for example in coating, impregnating or binding agents(solutions, disper sions, emulsions) for textiles, fleeces, papers,leathers;

h. as additives to a wide variety of industrial products to reduce thespeed of their ageing, for example as additives to glues, adhesives,paints or the like.

If the protective compounds of this invention are to be used for thetreatment of textile organic materials of natural or synthetic origin,for example textile fabrics, they may be applied to the substrate to beprotected at any desired phase of the final processing of the latter,such as during a dressing or anticrease finishing or dyeing process orduring any other finishing operation, by way of a fixing operationsimilar to a dyeing process.

Furthermore, the new stabilizers to be used according to this inventionmay be added to or incorporated with the materials prior to or duringtheir shaping. Thus, for example, they may be added to the moulding orinjection moulding compositions used in the manu facture of films,foils, tapes or mouldings or they may be dissolved or dispersed or inany other way finely distributed in the spinning mass before it is spun.The protective compounds may also be added to the starting substances,reaction mixtures or intermediates used in the manufacture of fullysynthetic or semisynthetic organic materials, that is to say also beforeor during the chemical reaction, for example in a polycondensation(including precondensates), in a polymerization (including prepolymers)or in a polyaddition.

An important shpere of application of the stabilizers to be used in theinvention consists in incorporating these substances in a protectivelayer used to protect material placed underneath. This application maytake the form of applying the ultraviolet absorber to the surface layer(of a film or of a fibre or of a multidimensional shaped object). Thiscan be done for example similar to a dyeing process, or the activesubstance may be embedded in a polymer (polycondensate or polyadduct)film by one of the known surface coating meth ods with polymericsubstances, or the active substance may be dissolved in a suitablesolvent and caused to diffuse or swell into the surface layer. Accordingto another important variant the ultraviolet absorber is em bedded in aself-supporting, substantially twodimensional carrier material, forexample a foil or the wall of a vessel, in order to keep ultravioletrays away from the substance located behind it (relevant examples: shopwindows, films. transparent packages. bottles).

From the foregoing it is self-evident that in addition to the protectionof the substrate or carrier material containing the ultraviolet absorberalso other substances contained in the substrate or carrier material areprotected, for example dyestuffs, antioxidants, disinfectants,antistatics and other dressing agents, plasticizers and fillers.

Depending on the type of substance to be protected or stabilized. on itssensitivity or the form in which the protection and stabilization is tobe imparted, the requisite amount of stabilizer may vary within widelimits, for example from about 0.01 to 10% by weight, referred to theamount of substance to be protected. For most practical purposes,however, a quantity from about 0.05 to 2% will suffice.

Accordingly, as results from the foregoing, the process for protectingorganic materials from the effect of ultraviolet radiation and heatconsists in homogeneously distributing a compound of one of the formulael) to (31) in the organic material to be protected, or applying it tothe surface of said material or coating the material to be protectedwith a filter layer containing one of the compounds mentioned.

In particular, this is advantageously done by homogeneouslyincorporating a compound of the formulae (1 to (31) in substance or inthe dissolved or dispersed form in an amount of 0.05 to 2.0% by weight(referred to the weight of the material to be protected) in the organicmaterial to be protected before the latter undergoes its final shaping.

If the substance to be used according to this invention is to be appliedto the surface of the substrate to be protected, thus for instance afibrous material (fabric), this is advantageously done by immersing thesubstrate to be protected in a liquor in which the oxalic aciddiarylamides are dissolved or dispersed. Suitable relevant solvents are,for example, methanol, ethanol, acetone, ethyl acetate,methylethylketone, cyclohexanol and above all water. The substrate to betreated is left in the liquor for some time, similar to the way thatdyeing processes are carried out; as a rule, 10 minutes to 24 hours atl0to C suffice, during which, if desired, the liquor may be agitated.Finally, the material is rinsed, if necessary washed, and dried.

In many cases it is of advantage to use the light filters mentionedabove in combination with sterically hindered phenols or esters ofthiodipropionic acid or organic phosphorus compounds. It is thus in manycases possible to achieve at the same time an anti-oxidation effect;above all, when compounds of the formula l l are used, synergisticeffects are observed.

MANUFACTURING EXAMPLES AND INSTRUCTIONS Unless otherwise indicated,parts and percentages in the following manufacturing examples andinstructions are by weight.

Furthermore, unless otherwise shown in detail, alkyl groups (C,,H arealways n-alkyl groups.

A. A mixture of 44 parts of oxalic acid diethyl ester and 74 parts ofpara-anisidine in 300 parts of diehlorobenzene is heated and stirredovernight at C under nitrogen. To complete the reaction, the temperatureis then raised to C while at the same time distilling off the alcohol.On completion of the reaction, the batch is cooled, the precipitatedproduct suctioned off and washed with benzene and petroleum ether, toyield 78 parts of a product of the formula mi Mace" CO---E\'II 5 Theanalytically pure product, obtained by recrystallization fromdimethylformamide, melts at 270 to 271C.

calculated: C 63.99 found: C 64.10

B. 13,6 Parts of the compound of the formula are suspended in 150 partsof chlorobenzene, and 15.3 parts of acetic anhydride are added.

The reaction mixture is then heated until all has dissolved. To completethe reaction the batch is refluxed for another 2 hours (addition of moreacetic anhydride at the boil accelerates and completes the reaction).

The batch is cooled in an ice bath, mixed with 300 parts of methanol,and the precipitated product is suctioned off, to yield 15.05 partsmelting at l8l.5 to 185C. After two recrystallizations the product ofthe formula C l w OCH 011 000 NH- CO-- CO NI is obtained: intheanalytically pure from it melts at 184 to 185C.

calculated: C 60.67 found: C 60.37

For the esterification of the phenolic hydroxyl group by the abovemethod there may be used instead of anhydrides also aliphatic oraromatic acid chlorides.

C. 27.2 Parts of the compound of the formula Oil istoo -00 are taken upin 200 parts of dimethylsulphoxide and mixed with 28 parts of potassiumcarbonate and 40 parts of octylbromide, then stirred for 6 hours at 50to 55C. The reaction solution is then mixed with 200 parts of methanoland the precipitated product of the formula is suctioned off and washedwith methanol. Yield: 33 parts. The analytically pure product melts at214 to 215.5C.

C ,H,, O,N.

calculated: C 7254 found: C 72.48

D. A mixture of 146 parts of oxalic acid diethyl ester, 32.2 parts ofmeta-trifluoromethylaniline and 1 part of boric acid is stirred for 5hours at to C, with the alcohol formed being continuously distilled off.The melt is then dissolved in dimethylformamide and the product of theformula 5?) N S? E? F -C-C-l'i-" is precipitated with water. Yield,about 33 parts. The analytically pure product obtained by tworecrystallizations from alcohol melts at 160 to 161C and reveals thefollowing data:

m iu -2 2 n calculated: C 51.08 found: C 51.28

E. 29.7 Parts of the compound (50) shown in Table A [prepared asdescribed in Example A] are suspended in 400 parts of dimethylformamideand hydrogenated under atmospheric pressure in the presence of Raneynickel until the theoretical quantity of hydrogen has been absorbed(duration: 4 /2 hours; temperature raised up to 125C). The catalyst isfiltered off and water is added at the boil until a turbidity appears.After cool- F. When in the method described in Example A theparaanisidine is replaced by the calculated quantity of paraaminobenzoicacid, the product 0 Q g i C) mm. ""NH- 7 HO H (59) is obtained in ayield of 82%. It does not melt below 330C and reveals the followinganalytical data:

CHEHIZZOGNZEZ calculated: C 58.54 found: C 58.29

H 3.68 N 8.53% H 3.68 N 8.5471

89.3 Parts of the above compound (39) are suspended in 650 parts ofthionylchloridc and 5 parts of dimethylformamidc and stirred andrefluxed for 7 hours, during which the finely granular suspension turnsinto crystalline needleswithout dissolving completely. The batch iscooled. rapidly suctioned and rinsed with petroleum ether. The crudeproduct is dried for a short time in a vacuum cabinet and then boiledfor minutes with 1400 parts of dichlorobenzene. The undissolved matteris filtered off and the filtrate concentrated to two-thirds its volume.After cooling, the product in the form of needles is suctioned off andwashed with petroleum ether, and dried, to yield 71.6 parts of thecompound of the formula I which melts at 280C with decomposition andreveals the following analytical data:

m m -l z -z calculated: C 52.63 H 2.76 N 7.67 H 19.42% found: C 53 02 H2.80 N 7.70 H 18.987!

which, upon recrystallization from dimethylsulphoxide+alcohol. melts at319 to 321C and reveals the following analysis:

calculated: C 69.78

H 8.4 N 10.17% found: C 69.81 H 8 l 14.6 Parts of the-compounds aresuspended in an autoclave in 200 parts of dichlorobenzene. 3.4 parts ofliquid ammonia are poured in portionwise and the whole is allowed toreact for 2 hours each at C, C and C. The suspension is thensteamdistilled and the dried residue extracted for 15 minutes each with200 parts of dichlorobenzene and then with 200 parts ofdimethylformamide. The dried residue (5.5 parts) corresponds to theformula and does not melt below 350C.

lH H i 4 calculated: C 58.89 found: C 58.90

The compounds listed in the following Tables are accessible in anexactly analogous manner:

-- NH 1n the following Table A 35 y Column 1 formula number I Column 11structural formula NH-CH- (CH Column 111 melting point (uncorrected) in4C l 2 Column IV analytical data: C H N upper line calculated 5 40 lowerline found" t. p. --v

I I I I I I IV ocll H. 00 I w I H 252 254 63-99 5.37 9.53

NI1 cllll 63.99 5-36 9-43 [I l] V 0 0 NCCN 71.92 6.03 10.59 H 11 11 H275 Cl Cl H ll ll H 295-5 -Continued I II III IV 00 H' 95. (I 25 8674.95 9.95 4.60 NHCO 74 .71 9.86 4.63 2 87 m1-co---- HH-CO 240.5 77.654.74 8.2.5

3 142 73.87 9.48 5.07 OCH -\LJ- OO 97. EFF-O28 moo 41-93 4.02 12.20

Tables B umn I formula number; column II substituent Z in In thefollowing Tables B1 to B12 there are summarizcd compounds correspondingto formula (ll) and l2). and l3) to (24) respectively. In these Tablescollower line f0 und.

the preceding formula; column Ill melting point (uncorrected) in C; andcolumn IV analytical data for C, H and N. the upper line beingcalculated and the

1. A SYMMETRICAL OXALIC ACID DIARYLAMDE OF THE FORMULA
 2. A symmetricaloxalic acid diarylamide as claimed in claim 1 which corresponds to theformula
 3. A symmetrical oxalic acid diarylamide as claimed in claim 1and of the formula
 4. A symmetrical oxalic acid diarylamide as claimedin claim 1 and of the formula
 5. A symmetrical oxalic acid diarylamideas claimed in claim 1 and of the formula
 6. A symmetrical oxalic aciddiarylamide as claimed in claim 1 and of the formula
 7. A symmetricaloxalic acid diarylamide as claimed in claim 1 and of the formula
 8. Asymmetrical oxalic acid diarylamide of the formula
 9. A symmetricaloxalic acid diarylamide of the formula